How long do I have to wait?
'Aspettare' — stress the second syllable: 'a-spet-TA-re'. The double 't' is held slightly longer than in English.
Ask this when there is no electronic display at the stop and you need a rough idea of the wait time. It works for buses, trams, and even ferries.
'Devo' is the first-person singular of 'dovere' (must/have to). 'Aspettare' means 'to wait'. The structure 'devo + infinitive' expresses obligation, equivalent to 'I have to + verb' in English.
Quanto aspetto?
How long do I wait?
Very colloquial shortening common in informal speech.
Sa quando passa il prossimo autobus?
Do you know when the next bus comes?
Formal; asks specifically about the next bus rather than wait time.
C'è molto da aspettare?
Is there a lot of waiting to do?
Idiomatic; 'molto da aspettare' literally means 'much to wait'.
Italian buses are notorious for running late, especially in southern Italy. Locals often check apps like 'Moovit' or the city transport app rather than trusting posted schedules.